33773번 - Zid 서브태스크다국어

Mr. Malnar wants to put up a picture of himself on the wall. The wall can be represented as a matrix with $n$ rows and $m$ columns. Since he has placed his picture on the wall many times before, some positions still have nails embedded in them. Such positions are marked with the symbol "#", while empty spots are marked with the symbol ".".

The picture has a rectangular shape with arbitrary dimensions and is placed on the wall in a way that it covers a rectangular area. The picture can be placed on the wall if it covers at most one position that contains a nail.

Help Mr. Malnar calculate the number of ways he can place his picture on the wall.

The first line of input contains $n$ and $m$ ($1 ≤ n, m ≤ 500$), the dimensions of the wall.

In each of the next $n$ lines, there are $m$ characters $c_{ij}$, describing the wall. Each character will be either "." or "#" (without quotes).

In a single line of output, print the number of possible ways to place the picture on the wall.

Clarification of the first example: Each placement of the picture is valid as long as it covers at most one nail.

Clarification of the second example: The picture cannot be placed in a way that it covers positions $(3, 1)$ and $(4, 1)$ simultaneously.